The present disclosure relates to color conversion techniques and color management systems and software.
Devices that are capable of representing image data (e.g., monitors, printers, scanners, cameras) often have significant variations in color gamut, the range of colors producible by the device. To accommodate this range in device gamuts, a variety of color spaces, and color management systems and techniques have been developed. Color management enables different color space values to be mapped from one device's gamut to another's using color profiles, which define how color information is transformed into or out of a standard reference space called a profile connection space.
Using color management, a human's perception of color from one device representation to another can be kept close to constant, despite the variation in color capabilities of different devices. To assist in color management, the Commission Internationale de L′Eclairage (CIE) has defined various color spaces that are device-independent and encompass the full gamut of human vision, and can thus be used as profile connection spaces. Typical profile connection spaces in color management systems include CIEXYZ and CIELAB. LAB space is a color space having a luminance channel, L, and opponent color channels, A (greenred) and B (blueyellow).
A color profile defines how to transform color information from one color space to another, such as from a device-dependent color space into a profile connection space, or the reverse. Many color profiles also conform to a defined color profile architecture, which provides flexibility in their use. For example, the International Color Consortium (ICC) provides a defined color profile architecture commonly used in many color management systems. ICC profiles have been developed for many different color spaces.
In addition, some ICC members have recently proposed the inclusion of image state information in ICC profiles, which will allow the specification of the image state of a given image's data as being scene-referred or output-referred. Scene-referred image data is image data that represents estimates of the color-space coordinates of the elements of a scene. Output-referred image data is image data that represents the color-space coordinates of the elements of an image that has undergone color rendering appropriate for a specified real or virtual output device and viewing conditions.